Do you think I take things too personally?

Whenever I send a message to somebody and they don't reply, usually I take it as a hint that they don't want to talk to me (and me specifically), for personal reasons which they won't bother to explain. When I say hi to somebody or do something polite (eg. open the door) and they didn't thank me, I wind up uming that they were ignoring me because they don't think I'm worth their time and want to give me a subconscious hint towards it. And when people have to remind me of something, I always feel guilty because I'd like to prove myself responsible enough not to need reminders. Is all of this normal?